Is it just me or is the default smoke materal pretty useless? Or is it just a “base” for adding more nodes?
I see that there is a difference between smoke and vapour. Smoke has dark particles, and vape has clear particles. Other than that the physics seems to be similar.
So it is by now difficult to make very dense “smoke” that gets brighter and flatter in color like vape does. Any suggestions?
The default node setup is definitely there to be modified. If you take a look at it, there is an empty add shader node, which is designed to plug the flame into.
Using the attribute node, you can specify smoke density, colour, temperature and flame (where fire should be), so you are quite free to alter the material for the desired effect.
I found a post of all possible attribute inputs here:
Also, you can try swapping out the volume absorption with a volume scatter. I don’t know exactly what nodes you need for what you are looking for, but it may help.
I guessed so, yes 
But there wasn’t in the list an attribute for Sub Surface Scattering. When I plug an emmision controlled by at.density into the add shader, the smoke lights up, but it is not physically correct and has to be tuned to the scene. Plugging any non-emissive shaders into the add gives poor results.
It might be more complicated…
EDIT: sorry, didn’t see your bottom lines written 
Changing the vol.absoption to scatter, made it a little bit better actually, so thanks for that!